Jet propelled propeller or rotor blade



Dec. 22, 1959 H. A. BOUSHEY JET PROPELLED FROPELLER OR ROTOR BLADE 2 Sheets-Sheet 1 Filed Dec. 13, 1956 v INVENTOR HOMER A. BOUSHEY BY JWM ATTORNEYS Dec. 22, 1959 H. A. BOUSHEY JET PROPELLED PROPELLER OR ROTOR BLADE 2 Sheets-Sheet? Filed Dec. 13, 1956 INVENTOR HOMER A. Boususv ATTORNEY United States Patent JET PROPELLED PROPELLER 0R ROTOR BLADE Homer A. Boushey, Washington, D.C.

Application December 13, 1956, Serial No. 628,018

4 Claims. (Cl. 60-3935) This invention relates to jet propelled rotors or propellers and more particularly to means for improving the propulsive efiiciency of jet propelled rotors or propellers.

One of the principal objects of the present invention is to provide improved tip mounted mechanism for jet propelled rotors or propellers for increasing the propulsive eflicien-cy thereof.

Another object of the present invention is the provision of improved tip mounted mechanism which includes compressor means for increasing the mass flow of gas through the propulsivejets of propellers or rotors to thereby increase the overall efficiency thereof.

Yet another object of the invention is the provision of a tip mounted rotary compressor which does not produce objectionable gyroscopic forces on the rotating propeller or rotor.

Yet another object of the invention is the provision of improved means associated with the tip mounted compressor for driving the same.

A still further object of the invention is the provision, in combination with a tip mounted compressor, of an auxiliary or booster, hub-mounted compressor mechanism together with passageways within the propeller or rotor blades to lead the hub compressed gas to the tip mounted mechanism which will further increase the overall efiicien-cy of the jet propelled rotor or propeller, and which can also provide for after-burning of fuel for additional thrust during periods when added power is required.

Other objects and their attendant advantages will become apparent as the following detailed description is read in conjunction with the accompanying drawings wherein:

Fig. l is a schematic plan view of a jet propelled propeller or rotor blade illustrating one embodiment of the present invention; I

Fig. 2 is a schematic perspective view of a turbo-compressor which may be utilized with the structure of Fig. 1;

Fig. 3 is a perspective view of a second embodiment of the present invention;

Fig. 4 is a schematic cross-sectional View taken substantially on the line 4-4 of Fig. 3; and

Fig. 5 is a schematic view of a third embodiment of the present invention.

In the art of jet propulsion it is known that an increase of mass flow of gases at the exit of a propulsive jet engine increases the efficiency thereof. A principal means for increasing this mass flow in a conventional jet engine has been by means of a compressor, usually driven by the products of combustion of a vaporized or gaseous fuel, which serves to drive a turbine connected to the compressor. The air thus compressed serves not only to support combustion of the fuel but also mingles with the products of combustion and with the products is ejected rearwardly of the jet engine to impart a forward thrust thereto. This cycle of operation is utilized in the majority of jet engines for propelling jet driven aircraft and heretofore attempts have been made to adapt this cycle to so-called reaction or jet driven propellers and rotors, particularly jet driven helicopter blades. Results, however, have been unsatisfactory due to the fact that a rotary compressor mounted at the tip of a rotor blade sets up undesirable gyroscopic precessional forces. Endeavors to increase mass flow by use of hub mounted compressors have also been unsatisfactory because of the increased blade size required to conduct the air from the hub compressor to the blade tip. Other disadvantages have been the loss of work required to drive the compressor and the increased temperature of the air resulting from the compression which lowers the overall efficiency of the jet and tends to weaken the blade over its entire length.

The present invention overcomes the disadvantages of the prior art systems by utilizing a tip mounted rotary compressor mounted with its spin axis substantially perpendicular to the plane of rotation of the rotor or propeller. This arrangement substantially eliminates the gyroscopic effects which would be produced by a rotary body mounted so that its spin axis lay in the plane of rotation of the propeller or rotor. In addition, by pro viding a compressor rotating in the plane of the rotor or propeller, a flat pancake or radial type compressor can be utilized and the frontal area of the blade in the region of the compressor thereby reduced. Common to the various arrangements of the invention illustrated in the drawing and described below is a radial compressor having its spin axis perpendicular to the plane of rotation of the rotor or propeller. Also common to the various arrangements is a turbine for driving the compressor. Various means for operating the turbine are illustrated and described.

Referring now to Figs. 1 and 2, there is schematically illustrated a radial compressor 2 mounted at the tip of a rotary blade 3 with the spin axis of the compressor perpendicular to the blades rotation. The compressor 2 is of the centrifugal type having thin radial blades 4 (see Fig. 2) which compress air centrally received from an inlet 6 at the leading end of the jet element 8. The compressor is turbine driven and one simplified means for accomplishing this is i lustrated in Fig. 2 where the turbine blades 10 are mounted at the ends of the compressor blades. The turbine blades may receive operating fluid, via inlet 9, comprising vaporized fuel in unburned or partially burned condition projected onto the blades 10. These members are preferably reaction type blades whereby the fuel, after performing work, is defiected as indicated by the arrows 12 into the compressor space to be mingled with the compressed air therein and be transmitted therewith via a suitable passage 14 to a combustion chamber 16 located rearwardly of the turbo-compressor. A suitable spark producing element 17 there ignites the vaporized fuel, which ejects rearwardly of the jet element 3 through the exit 18 to pro duce thrust. Preferably, the fuel is vaporized prior to impinging on the turbine blades by the heat of combustion of the fuel in the combustion chamber. Fig. 1 illustrates a preferred means for accomplishing this by use of a coil 19 in the end of the fuel line 20 which is Wrapped around the combustion chamber 16. Fuels particularly suitable for producing the required energy, when vaporized, to operate the turbine in the arrangement just described, are the so-called monopropellants including, for example, ethylene oxide, ethyl nitrate, nitro methane and propyl nitrate.

In lieu of using vaporized fuel for driving the turbo compressor, it is within the purview of the invention to employ the products of combustion. for accomplishing this is illustrated in Figs. 3 and 4 where An arrangement.

the turbo-compressor element 27 is of the double faced type, having an inflow radial turbine 28 on the upper face and a centrifugal compressor 30 on the lower face. With particular reference to Fig. 3, air enters the compressor chamber through an inlet 32 on the leading edge of the rotor blade 34 and is compressed in the usual manner. From the compressor chamber, compressed air is led in the direction of the arrows 36 through a passage 33 which serially includes a combustion chamber 39 (Fig. 3) and into which fuel is injected via a conduit 4-0 through a conventional nozzle indicated at 41. "in the fuei is ignited and ejected into the outer periphery of the turbine chamber 42 as indicated by the arrows 44 in Figs. 3 and 4. The turbine 28, being of the inflow type, directs the products of combustion to a centrally located exhaust 46 from whence the products of combustion excess compressed air are ejected rearwardly to produce .n'ust.

Yet another system for driving the compressor is illustrated in Fig. 5. This arrangement is similar in principle of operation to jet devices known as ducted by-pass jets. That is to say, air is compressed at the rotor or propeller blade tip for the purpose of increasing mass flow through an exit but the compressed air does not, in normal operation, mingle with the products of cornbustion within the jet element but is bypassed around the combustion chamber and is ejected through the exit simultaneously with the products of combustion, the combination being arranged to act as an ejector-jet. The bypassed air may, if desired, while in the bypass passages, be mingled with fuel injected through auxiliary nozzles and thus be after-burned to increase thrust during periods when greater than normal power is required. The turbine, in the arrangement outlined, is preferably driven by the products of combustion resulting from fuel burned in compressed air supplied through a hollow rotor blade. This air may be compressed by centrifugal action of the rotating blade or by a hub mounted auxiliary or booster compressor or by a combination of both a booster compressor and centrifugal action.

Since in this arrangement of a jet rotor or propeller only a fraction of the total mass flow passes through the hollow blades, it follows that the airfoil section of the blades need not be so thick, nor the compression and resulting temperature of the blades so high, as for a jet rotor or propeller wherein all the mass flow passes through the blades. By passing only a fraction of the air through the blades, obvious improvements result.

Referring now to Fig. 5, a tip mounted jet element St? is illustrated which operates on the ducted bypass principle above described. As schematically illustrated, the element 51' has mounted therein a combined turbinecompressor wheel 52 similar to that illustrated in Fig. 4 except that there is no interconnection between the compressor or inlet chamber and turbine or combustion chamber. Only the compressor side of the turbine wheel 52 is shown though it should be understood that a turbine is mounted on the opposite side. The rotor blade as is hollow to provide a passage 56 connecting a hub mounted booster compressor 58, driven in synchronism with the rotor 54 through suitable gear mechanism (not shown), With the turbine element at the blade tip. Prior to entering the turbine chamber, fuel conducted by a conduit 61 is injected through a suitable nozzle 62 and then ignited to provide operating force for driving the turbine. After performing work, the products of combustion are ejected rearwardly through an exhaust passage 64 centrally located in an outer passage 6% and terminating at the exit 63 of the jet element 50, the combination of exit 63 and passages 64, and 63 being arranged to act as an ejectorjet.

The compressor, driven by the turbine, compresses air entering the compressor chamber through an inlet passage d at the leading end of the jet element 50. The air, upon being compressed, is then projected rearwardly through outflow passage 63 within the element 50 and exits therefrom in a substantially cold state simultaneously with and on all sides of the hot products of combustion exiting from the exhaust passage If desired, auxiliary fuel nozzles may be provdided in the passage 63 so that in periods of abnormal power requirements, additional fuel may be after-burned in the passage 68 to provide augmented thrust.

It is old in the art to bypass compressed, relatively cold air about the combustion chamber of a jet engine and to those skilled in the art, the advantages accruing from the increased mass flow provided by this arrangement are well-known and require no further elaboration. The arrangement described above, however, adapts the ducted bypass principle to jet propelled propellers or rotors and, in accordance with the invention, illustrates the application of the principle in conjunction with a tip mounted rotary compressor whose plane of rotation lies substantially in or is approximately parallel to the plane of rotation of a propeller or helicopter rotor.

It is believed from the above description that the operation of the various embodiments of the invention should be apparent. The mechanisms illustrated are exemplary of means whereby a compressor may be mounted at the tip of a jet propelled rotary blade and driven so as to operate in the plane of rotation of the blade to increase mass flow through the exit of the jet without subjecting the blade to undesirable gyroscopic precessional forces. It should be understood that the vention is not necessarily limited to a centrifugal type compressor since it will be apparent to those skilled in the art that other types of compressors, such as centripetal and axial flow types, could be utilized. It will also be apparent that the compressor and turbine need not be coaxially arranged but could, with but slight modification, be mounted side-by-side or otherwise arranged so that they operate in a plane or planes substantially parallel to the plane of rotation of the rotor blade. Obviously, where those members are not attached to a common shaft or wheel, suitable gearing would drivably connect the turbine and compressor and such gearing may be arranged to drive the compressor at different speeds and in different directions than the turbine. The invention is susceptible to these and various other modifications without, however, departing from the scope and spirit of the appended claims.

What is claimed is:

1. A rotary jet propelled blade having at its outer extremity a jet propulsion unit comprising an inlet, an exit and a combustion chamber therebetween, a turbine in said jet propulsion unit adapted to be driven by expansible gases flowing through said combustion chamber, and a rotary compressor adapted to be driven by said turbine to compress air entering said inlet, the axes of said compressor and turbine being substantially perpendicular to the plane of rotation of said blade.

2. A rotary jet propelled blade having at its outer extremity a jet propulsion unit comprising a combustion chamber, an inlet and an exit, a turbine in said jet propulsion unit adapted to be driven by expansible gases flowing through said combustion chamber, and a rotary compressor integrally and coaxially attached to said turbine for compr ssing air entering said inlet and for discharging compressed air through said exit, the axes of said compressor and turbine being substantially perpendicular to the plane of rotation of said blade.

3. A rotary jet propelled blade having at its outer extremity a jet propulsion unit comprising an inlet, an exit and a combustion chamber, a turbine in said jet propulsion unit, a rotary compressor adapted to be driven by said turbine to compress air entering said inlet, said compressor and said turbine operating in planes substantially parallel to the plane of rotation of said blade, and means in said jet unit for projecting expansible gases onto said turbine for driving the same.

4. A rotary jet propelled blade having at its outer exhaving an inlet, an exit and a combustion chamber, a turbine in said body member and a rotary compressor drivingly connected to said turbine for compressing air entering said inlet, said turbine and said compressor operating in planes substantially parallel to the plane of rotation of said blade, a fluid fuel conduit in said blade for conducting fuel to said combustion chamber for ignition therein, a second air inlet at the inner end of said blade and connected through said blade to said combustion chamber, other means for compressing the air supplied from said second inlet to said combustion chamber, means for conducting the products of combustion from said combustion chamber to said turbine to drive the same, conduit means in said body for conducting the products of combustion from said turbine to said exit, a

bypass conduit in said body member for conducting air compressed by said first named compressor around said last named conduit and to said exit for simultaneous discharge therefrom with said products of combustion.

References Cited in the file of this patent UNITED STATES PATENTS 2,409,177 Allen et al. Oct. 15, 1946 2,474,359 Isacco June 28, 1949 2,605,608 Barclay Aug. 5, 1952 2,690,809 Kerry Oct. 5, 1952 2,814,349 Berry Nov. 26, 1957 FOREIGN PATENTS 440,593 France July 13, 1912 459,724

Italy Oct. 4, 1950 

